The genotypic ratio is the number of times a particular genotype occurrs in the offsprings following a test cross.

As an example, a test cross between two organisms with same genotype, Tt for a heterozygous dominant trait will result in offspring with the following genotypes: 1 of TT, 2 of Tt, and 1 of tt. Thus, the predicted genotypic ratio is 1:2:1.